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Biomedical subjects

M Johnson

Publications and source records attributed to M Johnson.

At least 91 records · Page 5Linked to original sources
PubMed2001

Words in a sentence become less accessible when an anaphor is resolved.

A noun that identifies an entity in a discourse becomes less accessible following an anaphoric reference to another entity. The phenomenon cannot be attributed to ad hoc strategies, memory decay, or context checking. It occurs for both common and proper nouns and for nouns that identify both characters and inanimate objects. It is stronger for nouns that identify important entities, as opposed to more peripheral ones.

Cognition↗
PubMed2001

Nursing skill assessment within populations: scale development and testing.

This study examined the reliability and validity of an instrument to measure the skill level of registered nurses within an Australian state. Internal consistency and construct validity of the scale and subscales were investigated in a sample of 1223 registered nurses from varying practice areas. The scale consisted of 105 skills within 13 practice domains: nursing practice, professional practice, acute care, community and public health, rural and remote area nursing, service delivery, self-management, supervision, resource management, improving processes, training and development, research, and technology. Twelve subscales obtained reliability co-efficients of 0.85 or more, with one at 0.81. The 13 factors explained 64.5 per cent of the cumulative variance, adequately capturing the concept of nursing skill. This scale, and its subscales, represent valid and reliable tools for the assessment and monitoring of skill levels in a population of nurses, within some limitation.

Australia↗
PubMed2001

Older female inpatients in Arkansas.

The purpose of this study was to examine age and Major Diagnostic Categories (MDCs) and compare the variables to mortality and length of stay among inpatient women age 50 and over. Archival statistical data were obtained for 2,238 inpatients in a private, nonprofit hospital in 1998. The ages ranged from 50 to 107 years old, with a mean age of 71.21 years. Quantitative analyses were conducted to examine the data from a private, nonprofit hospital and determine if there were significant relationships between age, major diagnostic category, length of stay, and mortality in older women. The MDC distribution indicated that the highest frequency of diseases and disorders were in the following three systems: circulatory system, musculoskeletal system and connective tissue, and the digestive system. The average length of stay was 8.01 days. The 30-day readmission percentage and the 365-day readmission percentage were 12.24% and 28.02%, respectively. The mortality rate was 6%. In addition, 63.97% went home after discharge, and 67.07% were Medicare recipients. The risk of musculoskeletal diseases and disorders increased with age (p = .0001). The conditional probability of death was nearly nine times higher for the diseases of the nervous system, myeloproliferative diseases and disorders, poorly differentiated neoplasms and respiratory diseases. As age increased, the probabilities of a long hospital stay decreased. The mortality analyses found that the lowest probabilities of survival were in categories of myeloproliferative diseases and disorders, poorly differentiated neoplasms, and infectious and parasitic diseases. According to current health statistics, our society is getting older. Not only are people living longer, they are accessing more health care (American Association for World Health, 1999). Overall, the average life expectancy at birth has been identified at 76.5 years. The female has a longer life expectancy than the male, averaging 5.8 years longer. The highest life expectancy has been identified in the white female, who can expect to live to 79. The black woman has the second-highest life expectancy, 74.7 years. Peters, Kochanek, and Murphy reported an all-time-low age-adjusted death rate for the United States and a continuing trend in the decline in mortality for all age groups. With a growing number of people living longer, there is a need to know about the most common health issues that affect quality of life. The top three national causes of death in older Americans were diseases of the heart, malignant neoplasms, and cerebrovascular diseases/stroke. Arkansas health statistics mirror the national statistics. In April 1999, the Arkansas Department of Health reported that 30.5% percent of all female deaths were caused by heart disease. Malignant neoplasms were responsible for 20.1%, followed by cerebrovascular diseases at 10.8%. Other than three Connecticut hospital studies that explored the relationship of diagnosis code, mortality, and readmission, research is meager in this area. There is a need for hospital-based research that addresses the diagnosis categories and the relationship to age and other variables.

Age Factors↗
PubMed2001

The presence and properties of myocilin in the aqueous humor.

PURPOSE: To determine whether myocilin is present in the aqueous humor (AH) and to examine certain properties of this protein. METHODS: Human AH was obtained at the time of either glaucoma surgery or cataract extraction. Monkey AH was obtained at the time of death, and bovine aqueous was obtained from eyes delivered from an abattoir. Column chromatography was performed on aqueous samples to determine the approximate size of the myocilin present. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western blot analysis were performed using antibody prepared against a peptide sequence in myocilin. Analysis of the bovine proteins present in AH that were retained by a microporous filter was also performed using western blot analysis. RESULTS: By western blot analysis, myocilin was present in human, monkey, and bovine AH. The apparent molecular size of the myocilin present in the AH were greater than 250,000 Da, when quantified with a gel filtration column. Myocilin appeared to be hydrophobic and was one of the proteins that was retained on microporous filters that were obstructed by AH. CONCLUSIONS: Myocilin is a constituent in the AH. It appears that myocilin is a hydrophobic protein that may exist in an oligomeric state or in association with other proteins. Myocilin is retained by microporous filters and may be involved in the obstruction of these filters that occurs when AH is perfused through them.

Animals↗
PubMed2001

The effect of aloe vera gel/mild soap versus mild soap alone in preventing skin reactions in patients undergoing radiation therapy.

PURPOSE/OBJECTIVES: To determine whether the use of mild soap and aloe vera gel versus mild soap alone would decrease the incidence of skin reactions in patients undergoing radiation therapy. DATA SOURCES: Prospective, randomized, blinded clinical trial. SETTING: Radiation therapy outpatient clinic in a cancer center affiliated with a major teaching medical facility. SAMPLE: The mean age of the participants was 56 years. The group consisted of Caucasians (74%) and African Americans (26%). The ethnic mix was non-Hispanic (65%) and Hispanic (35%). METHODS: Prophylactic skin care began on the first day of radiation therapy. Patients cleansed the area with mild, unscented soap. Patients randomized into the experimental arm of the trial were instructed to liberally apply aloe vera gel to the area at various intervals throughout the day. FINDINGS: At low cumulative dose levels < or = 2,700 cGy, no difference existed in the effect of adding aloe. When the cumulative dose was high (> 2,700 cGy), the median time was five weeks prior to any skin changes in the aloe/soap arm versus three weeks in the soap only arm. When the cumulative dose increases over time, there seems to be a protective effect of adding aloe to the soap regimen. IMPLICATIONS FOR NURSING PRACTICE: Skin products used to treat radiation dermatitis vary among institutions. Nurses should be aware that some patients may be predisposed to skin problems. Nurses must be aware of newly developed products and research regarding these products so that effective treatment can be instituted.

Adolescent↗
PubMed2001

Fluticasone propionate compared with zafirlukast in controlling persistent asthma: a randomized double-blind, placebo-controlled trial.

OBJECTIVE: The objective of our study was to compare the efficacy and safety of fluticasone propionate (an inhaled corticosteroid) with zafirlukast (a leukotriene modifier) for persistent asthma. STUDY DESIGN: In this randomized placebo-controlled, parallel-group, double-blind, double-dummy trial, patients underwent an 8- to 14-day run-in period followed by 12 weeks of treatment with inhaled fluticasone propionate (88 mg twice daily by metered-dose inhaler), oral zafirlukast (20 mg twice daily), or placebo. POPULATION: We included a total of 338 persistent asthma patients, 12 years of age or older, using short-acting b2-agonists alone. OUTCOMES: measured Efficacy outcomes included changes in pulmonary function, asthma symptoms, rescue albuterol use, nighttime awakenings due to asthma, and quality of life. Safety outcomes included asthma exacerbations, adverse events, and clinically significant laboratory test results. RESULTS: After 12 weeks of treatment, patients taking fluticasone propionate experienced significantly greater improvements in all clinical parameters (symptom scores, percentages of symptom-free and albuterol-free days, albuterol use, and nighttime awakenings) compared with patients taking zafirlukast (P <.05) or placebo (P <.05). Treatment with fluticasone propionate resulted in significantly greater improvements in pulmonary function compared with zafirlukast (P <.05) or placebo (P <.05). Fewer fluticasone propionate patients (4%) had an exacerbation requiring oral corticosteroids compared with those taking zafirlukast (12%) or placebo (10%). CONCLUSIONS: Inhaled fluticasone propionate is more effective than zafirlukast in controlling asthma symptoms, improving pulmonary function, and improving quality of life for patients who are symptomatic with the use of short-acting b2-agonists alone.

Administration, Inhalation↗
PubMed2001

Treatment of migraine with targeted nutrition focused on improved assimilation and elimination.

This study was undertaken to assess the impact of three months of targeted nutritional therapy for migraine on health-related quality of life. The study is also intended to lend support to a theory that migraine is caused by an underlying dysfunction involving assimilation or elimination mechanisms. Forty people were selected from approximately 120 applications. Fourteen participants were selected from among those applicants within the authors' practices and 26 from applicants solicited via the Internet. Participants were required to complete the Medical Outcomes Trust Migraine Specific Quality of Life (MSQ) Questionnaire. Eighty percent of the study participants experienced significant and sustained improvements in quality of life during the 90 days of the study. The study instrument is specifically designed to measure quality of life improvement and thus does not solicit responses relative to number of migraine attacks or duration of each migraine. However, it should be noted that improvement in quality of life is likely due to a reduction in the duration and frequency of migraine attacks.

Adult↗
PubMed2001

Caring carers.

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Adaptation, Psychological↗
PubMed2001

Junior medical students' perceptions of an introductory hospice experience.

INTRODUCTION: The importance of palliative care education in the medical school curriculum is becoming more recognized. The purpose of this study was to assess medical students' perceptions of an introductory hospice experience. METHODS: Forty-one second-year medical students took part in an introductory hospice experience in which they were acquainted with a wide range of hospice services provided to patients and families by an interdisciplinary team involved in hospice care. In addition, the students visited patients' homes individually with an experienced hospice nurse or social worker. At the end of their experience, the students were asked to complete a multi-item evaluation questionnaire in order to share their perceptions of the hospice experience and their suggestions for improvement of the course. RESULTS: The students spent an average of four hours on their introductory hospice experience, and they indicated that all of their personal goals for their experience had been met. Suggestions for improvement of the course were to increase the amount of course time allotted and to provide further opportunity to see more patients. Overall, the students rated their experience as "above average" to "excellent." CONCLUSIONS: According to the medical students who participated, the introductory hospice experience was a worthwhile and valuable educational experience. An equal or increased amount of hospice time should be allotted in the education of future junior medical students.

Attitude of Health Personnel↗
PubMed2000

Circadian rhythm of serum total homocysteine in men.

Serum homocysteine levels were examined in a 24-hour study of 7 healthy and 5 diabetic men, revealing a statistically significant circadian rhythm (p = 0.030), normal concentrations of 11.83 +/- 1.2 vs 12.99 +/- 1.2 micromol/L, with peak values occurring during the evening (10:37 P.M.) and lowest levels occurring during the morning. These findings imply that increased atherosclerotic risk in insulin-resistant diabetics during morning hours does not appear to be explained by differences in homocysteine levels in the normal population.

Adult↗
PubMed2000

IV immunoglobulin does not reverse established weakness in MS.

BACKGROUND: Immunoglobulin (Ig) administration induces remyelination in the Theiler's virus model of MS. METHODS: A randomized, double-blinded, placebo-controlled trial of IV immunoglobulin (IVIg) was performed in patients with MS who had persistent muscle weakness that had been stable for between 4 and 18 months to determine whether this would improve muscle strength (primary outcome: isometric muscle strength). Patients received either IVIg (0.4 g/kg) or placebo daily for 5 days, then single infusions every 2 weeks for 3 months (total, 11 infusions). Muscle groups identified by clinical measures to have unchanging significant weakness were the major targets for therapeutic response (targeted neurologic deficit [TND]). RESULTS: IVIg was well tolerated. An interim analysis after 67 patients were enrolled indicated no difference in the degree of change in strength between treatment groups in either the TND or non-TND muscle groups at 6 months, and the trial was terminated. There was no apparent benefit in relapse behavior or impairment measures during the 6-month observation period. Nor was there apparent benefit in either patients who remained clinically stable or in those with evidence of disease activity. Patients with active MS during the trial worsened in both TND and non-TND muscle groups. This worsening was seen regardless of whether the clinical manifestations of disease activity involved the TND muscle groups. CONCLUSIONS: IVIg does not reverse established weakness in MS. Measurements of isometric muscle strength were reliable (reproducible) indices of strength and may be sensitive, objective methods to document functional changes in impairment in future MS trials.

Adult↗
PubMed2000

Changes in CD4 lymphocyte counts after interruption of therapy in patients with viral failure on protease inhibitor-containing regimens. Royal Free Centre for HIV Medicine.

OBJECTIVE: To describe the short-term changes in CD4 lymphocyte counts after the interruption of antiretroviral HIV therapy in order to increase the understanding of CD4 lymphocyte dynamics, and so that appropriate monitoring strategies can be designed. METHODS: We studied 35 HIV-infected patients with late-stage disease who had therapy interruptions leading to high viral load levels, median greater than 750 000 RNA log10 copies/ml, and in whom two CD4 cell counts (median 28 days apart) were available before beginning a salvage regimen. RESULTS: Overall, there was a substantial decline in CD4 cell counts from a median of 125 to 83 cells/mm3 in the average 28 day period, with median proportionate and absolute losses of 26% and 24 cells/mm3 per month, respectively (P < 0.008). This tended to be greater in individuals studied sooner after interrupting therapy (P = 0.03) and in those with CD4 cell counts above the pre-therapy baseline (P = 0.06). There was a strong negative correlation between the proportionate increase in viral load and the absolute change in CD4 cell count (-0.66, P = 0.0002). CONCLUSION: Patients with relatively advanced HIV infection interrupting antiretroviral therapy after failing a protease inhibitor-containing regimen require frequent monitoring because CD4 cell counts appear to fall quite rapidly, at least in the first few weeks after interruption.

Adult↗
PubMed2000

Substantial correlation between HIV type 1 drug-associated resistance mutations in plasma and peripheral blood mononuclear cells in treatment-experienced patients.

The correlation of detectable HIV-1 drug resistance mutations in plasma and PBMCs in patients extensively treated with all antiretroviral drug classes has not been fully elucidated. The detection of mutations in PBMCs may reveal resistant HIV-1 associated with past therapies. In addition, these measures in PBMCs may have a practical value when plasma virus is at low levels that are difficult to detect with current assays. The reverse transcriptase (RT) and protease (P) genes were analyzed for drug resistance, using an in-house method carried out on 36 paired samples of plasma and PBMCs from 12 treatment-experienced patients in order to investigate resistance in the two compartments. When viruses in plasma and PBMCs were analyzed by patient, the mean of the Cohen kappa values was 0.728 (substantial agreement). When viruses were analyzed by codon the mean of the Cohen kappa values was 0.715 (substantial agreement). Baseline samples were concordant at 280 of 288 (97%) codons analyzed. This study shows that a minority of mutations associated with previous therapy can be detected in PBMCs and not in plasma. Overall, mutations in plasma and PBMCs showed a substantial correlation in extensively treated patients, suggesting that either compartment is suitable for the detection of mutations as a virological guide for clinical care.

Anti-HIV Agents↗
PubMed2000

A new power law for determination of total (125)I seed activity for ultrasound-guided prostate implants: clinical evaluations.

PURPOSE: The intraoperative planning with peripheral loading approach is an important technique for ultrasound-guided transperineal prostate implant. In this paper a sphero-cylindrical dose model is described to generate a new power law or a look-up table for determination of the total (125)I activity required to deliver a prescription dose to a given prostate volume. METHODS AND MATERIALS: Dose calculations were based on the new standards for (125)I seeds (model 6711) implemented by the National Institute of Standards and Technology (NIST) in 1999. Using the sphero-cylindrical dose model with peripheral loading approach, a new power law for calculating total activity of radioactive iodine required to deliver a prescribed dose for the target volume was developed. Accounting for random variation of the seed positioning in the prostate and the current air-kerma strength standard of (125)I seeds, this new power law is formulated as follows: A (mCi) = 2.15 d (cm)(2.00) where A is apparent activity in mCi, or A (U) = 1. 69 d (cm)(2.00) where A is air-kerma strength in U, required to deliver a cumulative dose of 145 Gy to a prostate gland with an average dimension, d, in centimeters. RESULTS: The efficacy of using the new power law in prostate implants was demonstrated. For clinical evaluations of this new power law, 40 patients were chosen in 1998. The average D(90) of these 40 patients was 172.0 Gy (SD +/- 29 Gy). This means that on the average, 90% of the target volume received was 172.0 Gy. The average coverage index (CI) in this study was 94.7 (SD +/- 4.7). As a result, 94.7% of the target volume received the prescription dose. The dose homogeneity index (HI) which measured the degree of the dose inhomogeneity was 0.38 (SD +/- 0.21). CONCLUSION: This new and simple power law or a new mCi-volume look-up table for (125)I seed prostate implantation has been developed and formulated for clinical use. Clinical evaluations expressed in quantitative parameters such as D(90), CI, and HI in prostate implants have been thoroughly analyzed and clearly demonstrated the efficacy of this approach.

Brachytherapy↗
PubMed2000

Fas preassociation required for apoptosis signaling and dominant inhibition by pathogenic mutations.

Heterozygous mutations encoding abnormal forms of the death receptor Fas dominantly interfere with Fas-induced lymphocyte apoptosis in human autoimmune lymphoproliferative syndrome. This effect, rather than depending on ligand-induced receptor oligomerization, was found to stem from ligand- independent interaction of wild-type and mutant Fas receptors through a specific region in the extracellular domain. Preassociated Fas complexes were found in living cells by means of fluorescence resonance energy transfer between variants of green fluorescent protein. These results show that formation of preassociated receptor complexes is necessary for Fas signaling and dominant interference in human disease.

Animals↗
PubMed2000

Viral genetic heterogeneity in HIV-1-infected individuals is associated with increasing use of HAART and higher viremia.

OBJECTIVE: To assess the correlation between the outgrowth of mutant viruses (viral genetic heterogeneity), highly active antiretroviral therapy (HAART), and plasma HIV-1 RNA in a population-based observational cohort study. DESIGN: The study population consisted of 42 HIV-1-infected individuals receiving at least two nucleotide reverse transcriptase (RT) inhibitors and one or more protease inhibitors at study entry. There were no restrictions on antiretroviral therapy after enrollment. METHODS: Plasma samples were obtained from subjects at baseline, at therapy changes, and at quarterly intervals for quantitation of HIV-1 RNA levels and for sequence determination of the entire protease coding region and the first 235 codons of the reverse transcriptase coding region. Data were analyzed using the generalized estimating equation method for longitudinal data and using linear regression analysis. RESULTS: With increased time on HAART there were significant increases in the number of total HIV-1 mutations in the regions sequenced (P = 0.010). There were significant correlations between the increases in the plasma HIV-1 RNA levels and the numbers of total mutations and reverse transcriptase mutations (P = 0.007 and 0.021, respectively). CONCLUSIONS: The number of HIV-1 mutations increased over time. Failure of HAART in this study population was correlated with outgrowth of virus with numerous mutations in the reverse transcriptase and protease coding regions. Phenotypic results correlated with genotypic results, showing decreased susceptibility to antiretrovirals over time in the majority of this population during HAART. Both synonymous and non-synonymous mutations were observed, with a higher incidence of non-synonymous mutations occurring at codons associated with drug resistance.

Adult↗
PubMed2000

Urinary morbidity with a modified peripheral loading technique of transperineal (125)i prostate implantation.

PURPOSE: Analysis of urinary morbidity within the first 12 months following a modified peripheral loading technique for permanent transperineal transrectal ultrasound (TRUS) guided (125)I prostate implantation and comparison of urinary morbidity with various clinical and implant parameters. MATERIALS AND METHODS: Between October 1, 1996, and March 11, 1998, 87 patients with favorable, early stage prostate cancer were treated with permanent transperineal TRUS guided (125)I prostate implantation. A peripheral loading technique was utilized for source placement with 75-80% source distribution in the periphery and 20-25% source distribution centrally. A mean total activity of 38 mCi of (125)I was implanted (range, 19-66 mCi). The mean source activity was 0.43 mCi/source (range, 0.26-0.61 mCi/source) and the mean number of sources implanted was 88 (range, 56-134). The minimum prescribed dose to the prostate was 145 Gy. The median D(90), V(100), and V(150) were 152 Gy (range, 104-211 Gy), 92% (range, 71-99%), and 61% (range, 11-89%), respectively. The median follow-up time was 19 months (range, 12-29 months). Urinary morbidity was scored at 3 weeks and then at 3-month intervals for the first 2 years using a modified Radiation Therapy Oncology Group (RTOG) grading system (scale 0-5). RESULTS: Most patients developed at least minor urinary symptoms with frequency or nocturia being the most common. Overall, 79% (69/87) of patients experienced urinary morbidity with 21% (18/87) reporting no symptoms. The incidence of overall Grade 1 urinary morbidity was 37% (32/87); Grade 2 morbidity was 37% (32/87); and Grade 3 morbidity was 6% (5/87). There was no Grade 4 or 5 morbidity. The incidence of Grade 0 frequency/nocturia was 36% (31/87); Grade 1 was 33% (29/87); Grade 2 was 30% (26/87); and Grade 3 was 1% (1/87). Grade 0 dysuria was seen in 56% (49/87) of patients; 32% (28/87) had Grade 1; 10% (9/87) Grade 2; and 1% (1/87) Grade 3 dysuria. Most urinary symptoms started a few weeks after implantation and began to subside by 6 months. At 12 months, 22% (19/87) of patients had persistent urinary symptoms (78% Grade 0, 15% Grade 1, 3% Grade 2, and 3% Grade 3). The mean urethral point dose was 174 Gy (range, 99-315 Gy). The mean number of sources implanted correlated significantly with the likelihood of developing acute urinary morbidity (p = 0.03). The total activity implanted also correlated with the morbidity outcome dysuria (p = 0.01) with a threshold seen at 37 mCi. Urethral point dose, source activity, intraoperative TRUS prostate volume, D(90), V(100), V(150), patient age, pretreatment PSA, Gleason score, and T stage did not correlate with morbidity. CONCLUSIONS: Permanent transperineal TRUS guided (125)I prostate implantation using a modified peripheral loading technique is associated with mild urinary morbidity that resolves in 78% of patients by 12 months. Grade 3 urinary morbidity was encountered in only 6% (5/87) of patients. Urinary morbidity may be related to the total number of sources implanted and/or the total activity implanted. Overall urinary morbidity was not correlated with urethral point dose, source activity, intraoperative TRUS prostate volume, D(90), V(100), V(150), patient age, pretreatment PSA, Gleason score, and T stage. The low incidence of urinary morbidity may be a consequence of our modified peripheral loading technique and/or the selection of patients with good-to-excellent preimplant urological parameters. Longer follow-up is necessary to assess biochemical control rates and long-term morbidity.

Aged↗